Authors

Document Type

Article

Publication Date

2017

Publication Title

The Auk: Ornithological Advances

Volume Number

134

Issue Number

3

DOI

10.1642/AUK-16-214.1

Abstract

Males of many animal species display to attract and stimulate potential mates. In socially monogamous species, males will court females both to establish a pair bond and to solicit extrapair copulations. We investigated whether paired and unpaired male Dark-eyed Juncos (Junco hyemalis) differ in their courtship of a novel female and whether their courtship behavior is related to their morphology or circulating hormones. We conducted simulated courtship interactions (SCI) by presenting free-living paired and unpaired males with a live, caged conspecific female accompanied by playback of a precopulatory trill, a signal of female receptivity, and tested predictions of multiple hypotheses. We quantified courtship behaviors for 20 min and then captured the males, measured them, and collected blood samples to quantify circulating post-SCI testosterone and corticosterone levels as well as restraint-induced corticosterone. Paired males approached the female more rapidly and spent more time in close proximity to the female than unpaired males. Paired males were also more active and spent more time with body feathers fully erect, but sang fewer songs, compared to unpaired males. Unpaired males were smaller in mass than paired males and had higher post-SCI corticosterone and restraint-induced corticosterone than paired males, but the groups did not differ in post-SCI testosterone. We discuss whether these findings should be interpreted as differences in how males court when seeking a social mate vs. an extrapair mate or as inherent differences between successful and unsuccessful males.